Yuto and Lian are at train stations 1,880 kilometers apart. Yuto boards a train heading east at an average speed of 220
kilometers per hour. At the same time, Lian boards a train heading west on a parallel track at an average speed of 250
kilometers per hour. How far has Lian traveled when the two trains pass each other?
Time
(h)
Rate
(km/h)
220
250
Distance
(km)
220t
250t
Yuto
Lian
470 kilometers
880 kilometers
940 kilometers
1,000 kilometers

1,000 km

Step-by-step explanation:

Assume that when two train pass each other, Lian has traveled x (km)

=> The time Lian has traveled when two trains pass each other is:

Time = Distance/ Rate = x/ 250 (hour)

As Lian and Yuto travelled from the two opposite train stations and the train stations are 1,880 km apart

=> When two train pass each other, Yuto has traveled 1,880 - x (km)

=> The time Yuto has traveled when two trains pass each other is:

Time = Distance/ Rate = (1,880 - x)/220 (hour)

As Lian and Yuto board at the same time, so that when two trains pass each other, the time both of them have traveled is equal

=> x/ 250 = (1,880 - x)/220

=> 220x = 250 x (1,880 -x)

=> 220x = 470,000 - 250x

=> 470x = 470,000

=> x = 1,000

So that, when two train pass each other, Lian has traveled x = 1,000 km

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3